@interface BlockViewController2 ()
@property (nonatomic, strong) NSTimer *timer;
@end
@implementation BlockViewController2
- (void)viewDidLoad {
    [super viewDidLoad];
    self.timer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];
}
- (void)onTimer {
    NSLog(@"-- timer --");
}
- (void)dealloc {
    NSLog(@"dealloc 2 = %@", self);
    [self.timer invalidate];
}
@end

- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];
    [self.timer invalidate];
    self.timer = nil;
}

/// Creates and returns a new NSTimer object initialized with the specified block object. This timer needs to be scheduled on a run loop (via -[NSRunLoop addTimer:]) before it will fire.
/// - parameter:  timeInterval  The number of seconds between firings of the timer. If seconds is less than or equal to 0.0, this method chooses the nonnegative value of 0.1 milliseconds instead
/// - parameter:  repeats  If YES, the timer will repeatedly reschedule itself until invalidated. If NO, the timer will be invalidated after it fires.
/// - parameter:  block  The execution body of the timer; the timer itself is passed as the parameter to this block when executed to aid in avoiding cyclical references
+ (NSTimer *)timerWithTimeInterval:(NSTimeInterval)interval repeats:(BOOL)repeats block:(void (^)(NSTimer *timer))block API_AVAILABLE(macosx(10.12), ios(10.0), watchos(3.0), tvos(10.0));
/// Creates and returns a new NSTimer object initialized with the specified block object and schedules it on the current run loop in the default mode.
/// - parameter:  ti    The number of seconds between firings of the timer. If seconds is less than or equal to 0.0, this method chooses the nonnegative value of 0.1 milliseconds instead
/// - parameter:  repeats  If YES, the timer will repeatedly reschedule itself until invalidated. If NO, the timer will be invalidated after it fires.
/// - parameter:  block  The execution body of the timer; the timer itself is passed as the parameter to this block when executed to aid in avoiding cyclical references
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)interval repeats:(BOOL)repeats block:(void (^)(NSTimer *timer))block API_AVAILABLE(macosx(10.12), ios(10.0), watchos(3.0), tvos(10.0));

self.timer = [NSTimer timerWithTimeInterval:1.0 repeats:YES block:^(NSTimer * _Nonnull timer) {
        NSLog(@"-- timer -- ");
    }];
    [[NSRunLoop currentRunLoop] addTimer:self.timer forMode:NSDefaultRunLoopMode];

self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 repeats:YES block:^(NSTimer * _Nonnull timer) {
        NSLog(@"-- timer -- ");
    }];

@interface CCTimer : NSObject
- (void)startTimer;
- (void)stopTimer;
@end

#import "CCTimer.h"
@implementation CCTimer
{
    NSTimer * _timer;
}
- (void)startTimer {
    _timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];
}
- (void)stopTimer {
    if (_timer == nil) {
        return;
    }
    [_timer invalidate];
    _timer = nil;
}
- (void)onTimer {
    NSLog(@"-- timer --");
}
- (void)dealloc {
    NSLog(@"-- timer dealloc -- ");
}
@end

- (void)viewDidLoad {
    [super viewDidLoad];
    self.ccTimer = [[CCTimer alloc] init];
    [self.ccTimer startTimer];
}
- (void)onTimer {
    NSLog(@"-- timer --");
}
- (void)dealloc {
    NSLog(@"dealloc 2 = %@", self);
    [self.ccTimer stopTimer];
    [self.timer invalidate];
}

@interface CCProxy : NSProxy
- (instancetype)initWithObject:(id)obj;
+ (instancetype)proxyWithObject:(id)obj;
@end

//
//  CCProxy.m
//  MemoryManageDemo
//
//  Created by Ternence on 2021/5/17.
//
#import "CCProxy.h"
@interface CCProxy ()
@property (nonatomic, weak) id obj;
@end
@implementation CCProxy
- (instancetype)initWithObject:(id)obj {
    self.obj = obj;
    return self;
}
+ (instancetype)proxyWithObject:(id)obj {
    return [[self alloc] initWithObject:obj];
}
- (void)forwardInvocation:(NSInvocation *)invocation {
    if ([self.obj respondsToSelector:invocation.selector]) {
        [invocation invokeWithTarget: self.obj];
    }
}
- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel {
    return [self.obj methodSignatureForSelector:sel];
}
@end

CCProxy *proxy = [[CCProxy alloc] initWithObject:self];
    self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:proxy selector:@selector(onTimer) userInfo:nil repeats:YES];